The present invention deals with an impeller. More particularly, it deals with an impeller which has a central hub part and a plurality of vanes extending therefrom.
Impellers of the above mentioned general type are known in the art. One of such impellers is disclosed, for example, in U.S. Pat. No. 4,358,245. During operation of such impeller in other words when the impeller rotates, a disturbing rotation sound occurs. It is especially undesirable when the impeller is used as a blower for cooling of an internal combustion engine of a power vehicle.